what are my options?

[Albert]

Just bought another machine, the plate says it uses 38amp of current, its a 25hp machine I am told.

I will be using the compressor 7.5kw (15amp)

and the extractor 4kw (8amp)

while using this machine.

I only have 63amp, 3 machines above will result in 38+8+15 = 61amp.

I am very close to the borderline.

I think I will definitely need a VSD to limit the startup current to 38amp. the machine does have star - delta but it will still result in 3 x full load current which is 100amp upwards.

would I need to upgrade the mains to 100amp?

is there any other options out there?

Thank you for your time.

[elanjacobs]

For reasons beyond my knowledge, star current doesn't appear to matter that much.
Our wide belt sander at work has a 30hp on the 1st head and 20hp on the second head. The on-board ammeters show that each motor draws well over 80A when winding up, but we can start both at the same time with everything else in the factory running even though we only have 100A coming in.

I'd just try it as is and see what happens.

[yowie]

It will probably be fine. If you have problems at start up, change the breaker on the 38amp machine to a D curve instead of what you probably have, being a C curve. D curve is designed for this application.

[Albert]

For reasons beyond my knowledge, star current doesn't appear to matter that much.
Our wide belt sander at work has a 30hp on the 1st head and 20hp on the second head. The on-board ammeters show that each motor draws well over 80A when winding up, but we can start both at the same time with everything else in the factory running even though we only have 100A coming in.

I'd just try it as is and see what happens.

Thats a lot of amp drawn from the sander! Will try see how it goes.... Am in residential area meaning I need to put RCD on these things.

[elanjacobs]

Thats a lot of amp drawn from the sander! Will try see how it goes.... Am in residential area meaning I need to put RCD on these things.
I know:oo:
It's just when the motors wind up, once it switches to delta they sit at about 11A each with no load.